Improved artificial leg



i" cord and foot.

-1 "1 y tm SAMUEL B: Jnvvnrr, or LAcoNIA, NEW HAMPSHIRE.

lfattersllatcnt No. 97 ,647 lated December 7, V15569.

mpnovnn ARTIFICIAL Lne.

flo allivhom `t'tmag/ concern Y Be it known .that I, SAMUEL B. Jnwn'rr, of' La- 'conia,.in the county of Belknap, and YState of New Hampshire, have invented a new and useful Improvement in Artificial Legs; and I do hereby declare that the following is a full and exact'description thereof, reference being had to the accompanying drawings, and to .the lettersof reference marked thereon. x My invention consists of a peculiar link for attaching the heel-cord to the thigh, without interferir] g with the knee-joint.

. Figure 1 i's a side view ofmy improved leg.

. Figure 2 is the same, partly dared. Y

Figure 3 isa section of the sa1ne.-

Figurel is a view showing the motion of the heel Figure 5 isacross-section of the foot.,

v Figure 6 is a detached view of the toe.

Figure 7 is a detached view of the link for heel-cord. Figure Siska bottom view of the foot, showing the line of travel.

In the'construction' of my improved artificial leg,r thethigh, leg, `and foot may beof the usual general form, with the kneepivot, ankle-pivot, kneefcords, and

toe-cord or spring, all `arranged in the ordinary manner, as shown in the accompanyingdrawings,iig 2, and 3."

r .'At apoint, say' aboutifive-eighths-of an inch for'iirarh and above the knee-pivot A, a bolt is inserted throughthe thigh, as seen at B, fig. 3.

When the `leg is extendeug-a line connectingthe knee-pivot and the bolt B, would stand at about an` angle of forty-ve degrees from a vertical or a horizontal line.

, Upon this bolt B is swung a link, D, through which the 'knee #pivot passes, without touching the same.

" This link isvery broad, in order to let the knee bend y or` extend, without interference with the knee-pivot,

pas shown in figs. Zand 4.

rlhe heel-cord C, I make very rrn and inelastic, so as to bear a great 4strain without stretching, and I attach this cord to the link D; By thisarrangement it will be seen that the flexion of the foot, and conse-f Thefoot acting like a lever," and-the heel being the short arm of the lever, about one-third vof the length of the foot, the strain upon the heel-cord may amount l -to live hundred pounds or more, according t-o the Weight of the person resting ontthe foot. Therefore, the heel-cord acts as a most powerful extensor4 of the knee, and it is impossible for the knee-joint togive' `way and let the patient fall.

The knee-pivotV and thepivotwhich connects or A' attaches the heel-cord or link D to the thigh, are placed in suoli relation to eaehotherthat the heel-oordnot only holds the leg when completely orl nearly extended, but thecord also may act as anextensor, until the knee is bent to an angle of forty-ve degrees, or to the dead centre.

As theknee is bent, the point B travels through lthe arc of a circle, as shown in broken lines in tig. 4. It will be .seen that the point B first rises in passing ,this arc, so'as to draw up the-heelatthe centre of the are, and then descends until it reaches the point B',

front of the knee-pivot to the rear of the saine, as the knee bends,`andthen returns again to the front lof the knee-pivot as'the leg is extended.

During this motion, the link D transfers the point B from side to side-of the knee-pivot, without any ini terference, as is clearly seen in lig. 4.

lhe` hinge of the toe-joint is made to conform to the shape of the natural foot.

Fig. 5 is a section of this joint, showing atrans'versesection of the foot and the pivot'E; Thehinge is so moulded to the form ofthe foot as to make no cavity '01"projection, whether the toe is flexed or extended.

I set the knee-pivot and anklelpivot nearly parallel to each other, so as to prevent the knee from turning outward as the knee is bent. Thus the ankle-pivot is set obliquely to the central vline of the foot, and at right angles to the line of travel, vas shown in fig. 8.

Having thus described my invention, I claim- The link I), substantially in purposes set forth.

,. S. "Bl JEWE-I'B Witnesses: y i

DANIELlBnEED i l WM, H. SAMAN.

the, manner and for the 'I 

